The invention relates to a buffer circuit for applying to an output terminal an output signal which substantially corresponds to a reference voltage.
Such a buffer circuit is used for applying a reference voltage applied to an input terminal in a buffered mode to an output terminal. In this case the buffering consists in providing an output signal which to the best possible extend corresponds to the applied reference voltage value, the output signal being capable of supplying an output current which is many times greater than the current the reference voltage applied to the input terminal can supply. Such a buffer circuit can be used in those cases in which there is a need for a reference voltage source having a high current-producing capacity, for example a supply voltage generator for generating, for example, 3.3 V across an integrated circuit, the supply voltage generator itself being fed by a 5 V supply voltage. In practice, the following, often conflicting requirements are imposed on buffer circuits of this type. They must be capable of correctly driving a load connected to their output, even when the load, considered in time, varies suddenly. They must be capable of supplying a highly variable output current and shall then not evidence a tendency to oscillate. At the same time the dependence on temperature of the buffer circuits must be as low as possible and they must have a lowest possible quiescent current consumption.